1. Technical Field
The present invention relates to a portable electronic device, and more particularly to a power management system having a switch able to respond to a closed state and an open state of a lid hingedly attached to the main body of a portable computer, in which power supplied to components of the portable computer is interrupted when the lid is closed.
2. Related Art
Compact and lightweight notebook and laptop computers have become increasingly popular due to their portability. In general, such a portable computer is composed of a main body having a keyboard and a lid, where the lid is hingedly attached to the main body of the portable computer. A flat panel display is typically mounted on the lid. Or in some instances it could be said that the flat panel display forms a lid covering the keyboard of the main body. Usually, the lid is closed when the portable computer is not in use. With the use of a latch device it is locked in the closed position to prevent the lid from being inadvertently opened. Thus, safe movement of the portable computer is possible.
Examples of latches for lids of portable computers are disclosed in U.S. Pat. No. 4,901,261 for Retractable Handle and Latch for Portable Computers issued to Fuhs and U.S. Pat. No. 5,580,107 for Hidden Latch Hook for Portable Personal Computer and the Like issued to Howell. An example of a complete housing for a portable computer is disclosed in U.S. Pat. No. 5,175,672 for Housing Apparatus for Portable Computer Systems issued to Conner et al.
Examples of methods and devices able to detect an open/closed state of a cover of a computer are disclosed in U.S. Pat. No. 5,235,532 for Information Processing Apparatus for Performing Operations in Response to the Opening and the Closing of a Cover Thereof issued to Sugino, U.S. Pat. No. 5,303,171 for System Suspend on Lid Close and System Resume on Lid Open issued to Belt et al., U.S. Pat. No. 5,077,551 for Display Panel Open/Closed Detection Mechanism, and Portable Electronic Apparatus Using the Same issued to Saitou, and U.S. Pat. No. 5,634,137 for Method and Apparatus for Updating System Configuration Based on Open/Closed State of Computer Housing Cover issued to Merkin et al.
In order to use the portable computer, the aforementioned latch is manually released and the flat panel display can be moved to the desired open position. When the portable computer is powered on and computer work is proceeding, the work may be interrupted by some matter or the computer may need to be moved. Then one may close the flat panel display before leaving the desk or moving the portable computer. Closing the lid with the power on may prevent heat dissipation through the top surface of the main body and this will affect system components due to excessive heat between the main body and the flat panel display.
In order to avoid this, the portable computer users may quit the program and turn off the power before closing the lid. Further, if the portable computer supports advanced power management (APM), the user may invoke the suspend mode by pressing special function keys. Suspend mode can be automatically invoked when the system is not used for a predetermined time interval. After the suspend mode is invoked, a central processing unit (CPU) clock is stopped and most power managed devices are not powered. When the system is first switched to the suspend mode, a basic input/output system (BIOS) program saves the current memory and system information to disk before the system goes to power-off status. When the system is turned on after being in the suspend mode, the system information is retrieved from the disk to resume normal operations. This power management is especially useful for portable computers to enable them to use less power while the system is running on battery power.
Examples of suspend systems for computers are disclosed in U.S. Pat. No. 5,021,983 for Suspend/Resume Apparatus and Method for Reducing Power Consumption in Battery Powered Computers issued to Nguyen et al. and U.S. Pat. No. 5,630,142 for Multifunction Power Switch and Feedback LED for Suspend Systems issued to Crump et al.
Note that turning off system power before closing the lid as well as pressing special function keys invoking the suspend mode is inconvenient and time-consuming since it requires manual operation and needs confirmation that the system has gone into power-off mode. In addition, when the computer work should be resumed, opening the lid and turning on the system power is also inconvenient.
Although presently there do exist power management systems for portable computers, I have discovered that it would be desirable to develop an enhanced power management system for portable computers.